Thermoelectric driven gas well heat pump

ABSTRACT

A system for providing heat to natural gas well pipes and equipment uses a thermoelectric generator to supply electricity to a motor and gear pump. The thermoelectric generator drives a DC brushless motor and gear pump in order to circulate heated glycol from a dehydrator through a heating tube to thereby heat the pipes and equipment. Batteries may be used to buffer the power supply to prevent overloading the thermoelectric generator.

PRIORITY

The present application claims the benefit of U.S. Provisional Application Ser. No. 61/161,271, filed Mar. 18, 2009, which is herein incorporated by reference in its entirety.

THE FIELD OF THE INVENTION

The present invention relates to the heating of piping and valves on natural gas wells to prevent freezing. More specifically, the present invention relates to a system for circulating heated fluids along the piping and valves where electrical power is not readily available.

BACKGROUND

Piping and valves for natural gas wells are prone to freezing, particularly in cold climates and during the winter months. Freezing of pipes and valves can interfere with proper control of the well and interfere with the production of the well. It is desirable to keep the pipes and valves from freezing in order to avoid these problems, as well as to avoid the labor and expense of thawing and possibly repairing the frozen pipes and valves.

One problem is that a good source of electrical power is typically not available at the gas wells, since these are often in fairly remote locations. This has prevented a reliable and efficient system for heating the pipes and valves. Previous systems have used natural gas from the gas well to operate a pneumatic pump in order to circulate heated glycol. These systems, however are both expensive to run and environmentally unfriendly as they vent a significant amount of natural gas to the atmosphere to drive the pump. There is a need for a system for heating the pipes and valves of gas reservoirs which is reliable and which operates without an outside electrical connection.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved system for heating gas well pipes and valves to prevent these from freezing.

According to one aspect of the invention, a thermoelectric generator is used as a source of power to operate a pump and heating system. The thermoelectric generator, while providing a relatively small amount of electrical power, can use natural gas as a fuel source and thus eliminates the need for outside electrical power. The thermoelectric generator is used in combination with heated glycol and with a motor and pump which provides sufficient heat to pipes, valves, and other necessary well parts to prevent freezing.

These and other aspects of the present invention are realized in a thermoelectric driven gas well heat pump as shown and described in the following figures and related description.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention are shown and described in reference to the numbered drawing wherein:

FIG. 1 shows a schematic view of the present invention.

It will be appreciated that the drawing is illustrative and not limiting of the scope of the invention which is defined by the appended claims. The aspects shown and discussed accomplish various objects of the invention.

DETAILED DESCRIPTION

The invention and accompanying drawing will now be discussed in reference to the numerals provided therein so as to enable one skilled in the art to practice the present invention. The drawing and description is exemplary of various aspects of the invention and are not intended to narrow the scope of the appended claims.

Turning now to FIG. 1, a schematic diagram of a heating system of the present invention is shown. The system typically includes a thermoelectric generator 10, a battery 14 (which may include one or more individual batteries in an array), a controller 18, a motor 22, a pump 26, and the heating line 30.

The thermoelectric generator 10 typically is supplied with natural gas from the gas well via a pipe 34. An example thermoelectric generator 10 is the Global Thermoelectric Generator model no. 8550-24. The thermoelectric generator 10 utilizes an array of thermocouples which are joined together electrically by cold junction cathodes. The hot junction of the thermocouples is maintained at a temperature of about 1000° F. by a burner consuming the natural gas fuel. The cold junction of the thermocouples is maintained typically at 235° F. or lower with a heat pipe which transfers heat to the air. The example thermoelectric generator is able to produce approximately 550 watts of power at 24 volts.

The electricity from the generator 10 is passed through a battery 14 which buffers the electrical power supply. A controller 18 may be used to operate the motor 22. As such, the motor may be a brushless DC motor which requires a controller 18. An example controller is the Anaheim Automation Controller MDC150-050301.

The motor 22 drives the pump 26 to circulate hot glycol. The motor is preferably a DC brushless motor, such as a 24 volt 20 amp brushless motor. The pump 26 is preferably a gear pump, such as the Oberdorfer gear pump N992R. The gear pump circulates heated glycol through a tube 30. The tube 30 is placed along pipes 38 and valves 42 to heat the pipes and valves. Typically, insulation will be placed around the pipes 38, valves 42, and tube 30. The tube 30 is also used to heat other valves and equipment where heat is necessary, and may be used at the well itself for heat. For simplicity, only a small section of pipe and a single valve is shown.

The glycol is typically supplied by a dehydrator 46. The dehydrator 46 is used to remove water from the natural gas produced by the well by contacting the natural gas with glycol, which draws the water into the glycol solution and produces a dried natural gas. The dehydrator uses natural gas as a fuel and produces heated glycol as a result. Thus, the tube 30 is connected to draw heated glycol from the dehydrator, circulate the glycol around the desired pipes, valves, etc. and return the glycol to the dehydrator.

The system is typically operated during the winter months. Thus, in cold climates the system is typically switched on at the onset of winter and remains on for the duration of the winter season.

The system is advantageous as it provides for heating and circulating glycol to heat pipes and valves where electrical power is not readily available. The system results in a significant reduction in the amount of natural gas which is consumed as compared to available gas pump driven systems, and also is more environmentally friendly, as it is quite efficient and produces carbon dioxide and water where the gas pump systems vent a larger amount of natural gas to the atmosphere. The system allows the glycol to be circulated through the tube 30 and heat the desired pipes and equipment while drawing only a very limited amount of power which is available from the thermoelectric generator.

There is thus disclosed an improved thermoelectric driven gas well heat pump. It will be appreciated that numerous changes may be made to the present invention without departing from the scope of the claims. 

1. A system for heating natural gas well pipes and equipment comprising: a thermoelectric generator having a burner and a plurality of thermocouples and configured for producing an electrical current; a motor operating from electrical current produced by the thermoelectric generator; a pump driven by the motor; a tube connected to the pump and having a heated fluid therein, the tube being disposed along pipe and equipment to thereby heat the equipment.
 2. The system of claim 1, wherein the system further comprises a battery disposed between the generator and the motor.
 3. The system of claim 1, wherein the motor is a brushless DC motor, and wherein the system further comprises a motor controller for receiving power from the thermoelectric generator and for driving the motor.
 4. The system of claim 1, wherein the thermoelectric generator uses natural gas as a fuel source.
 5. The system of claim 1, wherein the heated fluid is glycol.
 6. The system of claim 5, further comprising a natural gas dehydrator which uses glycol to remove water from natural gas, and wherein heated glycol from the dehydrator is circulated through the tube.
 7. The system of claim 1, further comprising insulation disposed around the tube and the equipment which is heated by the tube.
 8. A system for heating natural gas or oil well pipes and equipment comprising: a thermoelectric generator having a burner and a thermocouple array; the generator receiving a fuel supply from the well and for burning the fuel source to heat the thermocouple array and thereby produce electricity; a motor connected to the generator for receiving electricity therefrom to drive the motor; a pump connected to the motor such that the motor drives the pump; and a tube filled with a heated liquid and connected to the pump such that the pump circulates the liquid through the tube, the tube being disposed along well pipes or equipment to thereby heat the pipes or equipment.
 9. The system of claim 8, wherein the thermoelectric generator receives natural gas from a natural gas well as a fuel source, and wherein the system is used to heat pipes and equipment associated with said natural gas well.
 10. The system of claim 8, wherein the system further comprises a motor controller for receiving electricity from the generator and for operating the motor.
 11. The system of claim 10, wherein the motor is a DC brushless motor.
 12. The system of claim 8, wherein the pump is a gear pump.
 13. The system of claim 8, wherein the heated liquid is a glycol.
 14. The system of claim 13, wherein the heated glycol is from a natural gas dehydrator.
 15. The system of claim 8, further comprising insulation disposed to enclose the tube and pipes or equipment. 